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Re: Denotation of URIs

From: Peter F. Patel-Schneider <pfps@research.bell-labs.com>
Date: Wed, 09 Apr 2003 09:20:39 -0400 (EDT)
Message-Id: <20030409.092039.74194415.pfps@research.bell-labs.com>
To: Patrick.Stickler@nokia.com
Cc: www-rdf-interest@w3.org

From: <Patrick.Stickler@nokia.com>
Subject: RE: Denotation of URIs
Date: Wed, 9 Apr 2003 09:33:31 +0300


> > Ambiguity is difficult to deal with, agreed, and it is reasonable to try to
> > reduce it to the extent possible.  However, mandating that certain kinds of
> > ambiguity are not permissable, just means that one cannot deal with
> > situations where these kinds of ambiguity actually exist.  
> I disagree. One can mandate all kinds of constraints yet still provide
> machinery for dealing with violations of those constraints. A case in
> point are HTML browsers. The HTML specs are very clear about what is or
> is not a valid HTML instance, yet browsers are quite capable of dealing
> with errors in HTML instances.

HTML doesn't say that all documents that are non-valid HTML document are
supposed to cause a core dump; it is just silent how such documents are to
be treated, and many browsers do interesting things.

Let's then agree that your version of the Semantic Web is only concerned
with situations where denotation of URI references is fixed and universal.
I would then support you in any effort to state that the denoation of URI
references is fixed and universal given this assumption.  Feel free to work
under this assumption provided that you don't eliminate the possibility of
other visions of the Semantic Web that lift this assumption, which is what
you appear to have been attempting to do.

> The same is true for SW agents. Ambiguity in denotation should be clearly
> and strongly identified as bad, wrong, detrimental, etc. yet the SW 
> architecture can still have machinery to help identify any occurring
> ambiguity and deal with it productively.

Drawing a line around the part of the Semantic Web that needs this
assumption is fine.  When working in this part of the Semantic Web it is
also fine to try to identify parts of the Semantic Web that don't quite
satisfy the assumption and try to modify them as necessary to satisfy the

> Being able to deal with an error does not validate the error and make it OK.

Well, sure, if you view it as an error.  However, others may disagree, and
view it as a source of power.

> Ambiguity in denotation will always be a bad thing. Always. Even if SW agents
> can deal with it trivially (which I doubt they will be able to do short of
> cognitive abilities).

Ambiguity in denotation is a fact of communication.  Always.  SW agents
will eventually have to deal with it (and should be able to deal with some
ambiguity in denotation without full cognitive abilitities).   

It may be that some cognitive-like abilities are needed to deal with any
sort of ambiguity in denotation, but so what?  Aren't SW agents supposed to
have cognitive-like abilities?

> Patrick

Peter F. Patel-Schneider
Bell Labs Research
Received on Wednesday, 9 April 2003 09:20:50 UTC

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